How can I earn $600 in 4 months?

I need to try and earn $600 by April 2010. I'm 15 Years Old so I'm not really old enough to get a job in my area (the jobs in my area require you to be 16) I live in Michigan and it's cold and snowy this time of year. I'm open to all ideas! Please explainin as much detail as possible. Thank you.